The UK has a new policy to send send stoners to the slammer.

Cannabis will be raised to a class B drug with a maximum five year jail term for users, the government said on Wednesday, rejecting a recommendation from its own drugs advisers to leave the classification unchanged.

Home Secretary Jacqui Smith said the decision had been made because of concern, particularly amongst the public, about the “alarming” use of skunk, a stronger strain of the narcotic which now dominates the market.

“I want it to be clearly understood that this powerful form of cannabis is an illegal and harmful drug,” Smith told parliament, vowing the change would be backed by crackdowns on cannabis farms.

“There is a compelling case for us to act now, rather than risk the future health of young people.”

Her announcement followed the publication of a report by the independent Advisory Council on the Misuse of Drugs (ACMD) which said there was insufficient evidence to regrade cannabis to the more serious class B.

The UK had downgraded pot to a Class-C offense in 2004, reducing the penalty for smoking pot to a stern warning from the coppers. However, officers could still arrest repeat offenders and people smoking in public or around kids. But the reason bigwigs justified changing the policy to jail pot smokers for five damn years, according to the Home Secretary, was purportedly a shift in public opinion: Respondents to a survey said they believed today’s pot—which they call skunk—is more potent and more dangerous. And they are right about one thing, according to the research of the ACMD, it is more potent. Almost twice as potent. But cracking down on drugs is the reason it’s stronger. In the days of prohibition, hard liquor was all the rage—because a bottle of grain alcohol was easier to conceal than a keg of beer—and a growing a few plants of high-quality skunk is easier to conceal than a field of sativa.

But if the weathervane of public policy is public opinion, where does the British public stand on penalties for this super-bud? The poll found that “44% wished cannabis to remain Class C… and 19% wished it to be legalized.” Only 19 percent of the public wanted to increase the penalties.

The other justification is that more people are using this allegedly more-harmful pot. But according that pesky report: “…some cannabis smokers seek the maximum effects while others inhale only a sufficient quantity of THC to obtain a particular degree of intoxication.” (It bears mentioning that Marinol, the prescription pharmaceutical, is 100 percent THC.) The report (.pdf) continues, “Despite the high prevalence of cannabis use, particularly among young people… use appears to have declined by around 20% to 25% over the past five years in all age groups. Similar findings have been reported from a national survey of English secondary schools.” Yeah, that decline occurred in the years pot penalties decreased. So even if pot use is a problem, and pot is more potent, the number of people using it has gone down. Based on all this research, what were those recommendations again from Advisory Council on the Misuse of Drugs—based on concrete science? “Cannabis should remain a Class C drug.”

Because science indicates cracking down on pot—in the UK, or in the US—doesn’t reduce marijuana use. But why base drug policies on science?